Conversion of hydrocarbons



Patented Feb. 21, 1950 CONVERSION OF HYDROCABBONS Edwin T. Layng, NewYork, N. Y., assignorto The Polymerization Process Corporation, JerseyCity, N. J a corporation of Delaware No Drawing. Original applicationDecember 30,

1942, Serial No. 470,687. Divided and this application June 18, 1946,Serial No. 677,521

'1 Claims. (Cl. 260- 671) This invention relates to improvements incatalytic conversion processes which involve the activation of olefinhydrocarbons. Such processes include the polymerization of olefinhydrocarbons and the alkylation of iso-parafiin and cyclic hydrocarbonsby means of olefin hydrocarbons. A

The invention relates particularly to improvements in processes whichinvolve the activation of olefin hydrocarbons by means of solidcatalysts comprising phosphoric acid as the essential active ingredient.Such catalysts are prepared by impregnating suitable supporting materialsuch as carbonaceous granules with phosphoric acid which may be ineither the ortho or pyro form or by the compounding of the phosphoric.acid with siliceous materials, such as kieselguhr and clays which arereactive with a portion of the phosphoric acid. Such reaction provides asubstantially porous mass of the reaction product of the binder andphosphoric acid which acts as a support for the remainder of thephosphoric acid, the latter constituting the essential active ingredientof the catalyst. Catalytic material thus prepared is capable ofactivating olefin hydrocarbons in catalytic conversion processes in.-volving long operating runs resulting in a yield of product per unitquantity of catalyst which; is sufiiciently large to render it moreeconomical to replace the used catalyst at the end of each operating runwith fresh catalyst than to regenerate or reactivate the used catalyst.At the end of each operating run, therefore, theused catalyst .isremoved from the reactor and replaced with fresh material. I

At the end of such long operating runs it is found frequently that thegranular catalyst, mass has set into a rigid structure which isdifficult to remove from the catalyst chamber. Alternatively, thecatalyst is sometimes found as a plastic or sticky mass. Theseconditionsrnay result in part from changes in the chemical and physicalstate of the catalyst which form liquids which cause the catalystgranules to adhere. Adherence of the granules to each other is pro.-moted also by the cementing action of highly polymerized materials whichaccumulate on the surfaces of the catalyst granulesduring the op-vcrating run. The setting of the granular mass in this manner presents aparticularlydifficult task of removin it from reactors inwhich thecatalyst mass is contained in elongated .tubular. chambers. 1 Theeffects which promote setting of the catalyst rnass also tend to limitthe length of. the.

"mit great yield of useful product per unit of a facilitate the intimatemixing catalytic material.

boiling. polymers.

operating run. The formation of liquids softens This may cause de moldedcatalyst pellets. formation of the catalyst pellets with the result}that the mass becomes unduly consolidated and presents too greatresistance to the flow of the reactants therethrough. The accumulationof centers.

In this important application of, theinvention the diflicultiesattendant upon the removal of the used catalyst from the reactor areeliminated, and a greater yield of useful product per unit of catalystis achieved, by employing-as the con solidated granular mass in thereactor a mechanical mixture of the granular catalyst and granularmaterial which is substantially inactive catalytically. The volumetricratio of the gran--;

ular catalytic material to the granular substan tially non-catalyticmaterial may vary from 1:1 to 5:1 but the preferred ratios are from 2:1to 3:1. The'non-catalytic granular material conveniently isapproximately of the same granular dimension as the granular catalyticmaterial to thereof with the "the mass are minimized and by preventingchanneling of the reactants in the catalyst mass. The spacer materialfunctions to strengthen the catalyst mass as a whole, to absorb liquids,such as phosphoric acid and heavy polymers, to percatalyst employed andto permit easy removal of. the catalyst mass from the reactor at the endof the operating run. The absorption of xi these various liquids by thenon-catalytic spacer assists in retarding adherence of the catalystgranules and setting of the, catalyst mass and furthermore minimizesblanketing of active centers of the catalytic material by, the high Theretention' of these tarrypolymers by the granular spacer materialreduces the amount of such polymers in the liquid prod not and improvesthe color of the latter.

The materials which-are useful asthe nonl catalytic spacer materialsincludej,,in. general. m'aterialsflwhich are substantially non-reactivewith phosphoric 'acid. It is necessary, therefore,. to, avoid certainnatural materials, such as silica, kieselguhr, alumina,'clay, etc. .Ingenan isae ee a Oxides im s i 3 ticularly those ofthe alkali andalkaline earth series, should be avoided. Suitable materials include thenormal and acid salts of the various phosphoric acids which are notsubstantially reducible under the conversion conditions, such as thephosphates of calcium, strontium, barium,

Suitable materials include various charcoals and tainlargeamounts offree alkalior alkaline salts.

The spacer material must occur naturallyas, or

. be preformed into, granules of substantially the dimensions.ofthegranular or pelleted catalytic material. This requires thegranulation of certainmaterials such .asthe .phosphatesand other saltsmentioned above. .Itis preferred to employ granular charcoal. or othersuitable granular carbonaceousmaterial. Granular charcoal isparticularly suitable also because .of. its irelativ'ely highcapacityfortherabsorptionand retentionof liquidsiand good .mec'hanical strength.'While.

highly-activated charcoals, such as cocoanut charcoal,.are quitesatisfactory suchhighly'acti- I vated materials are not .necessary and aonly slightly activated charcoal hasbeen found. to be quitesatisfactory.

I The substitution of, such amixed-granular catalyst mass for oneconsisting ,entirelyof'the,

granular catalytic material in a reactor while charging hydrocarbons tothe reactor at thesame rate'results in a substantial increaseinithea'ctual space velocity of the operation because of the,

decreased volume of the space in the'reactor actually occupied bycatalytic material. In orderto maintain'the degree of conversion at thesame rate it may bedesirable in someinstancesz'to. increase the reactiontemperature slightly if this does-not substantially alter the characterof the liquid product obtained.

The substitution of the improved catalyst-mass,

comprising a mixture of thecatalyst granules with a substantialproportion-of granules of the non-catalytic spacer material, for acatalyst mass of the same volume consisting. entirely of the granularcatalytic material, and the passage of pressed in'terms ofvolume ofreactants-perunit volume of actual catalyst space. Under suchcircumstances theconversion rate may "declinetto the predetermined;minimum .in a: shorter ';time

' whereby the operating run must .be-termi-natediin .a shorteritime..jHowever, thesubstitution of the mixedgranular mass as described.above-results generally in .a longer, operating run, presumably becauseof the efiect of the porous'spacerrnaterial in absorbing and retainingliquids which might otherwise blanket the active surfaces of thecatalytic material. In all cases, however, whether the operating run islengthened or shortened by the new method, the yield of useful productper unit .of catalyst employed is increased because of the effect of theporous spacer in maintaining the activity of the catalyst.

Preferably sufficient reactor space is provided to accommodate thespacer material While leaving a remaining catalyst space sufficientlylarge to permit charging the reactants at the desired rate whilemaintaining the desired space velocity. In any case the yield of usefulproduct per unit of catalytic materialis'increased and the increasednumber of catalyst change-overs which may result from shortening theoperating run is com- -ipensated for by the substantial decrease in thetime required for cleaning the reactor in each change-over.

A. further advantage of the use of the spacer material results]. fromits effect in minimizing over-heatingof the catalyst as the result ofthe exothermic heat of reaction. As the reactants pass throughthereaction zone they pass through a zone of maximum temperature whichresults from contact of a relatively high concentration of olefinreactants with a body of relatively fresh catalytic material. As thecatalytic material which is contactedby the highest concentration ofreactants becomes-deactivated the concentration of reactants in contactwith a succeeding mass of catalysts is increased due to the lowereddegree of conversion which occurs during. thev flow of thereactants overthe deactivatedcatalyst. Consequently, there is, throughout theoperating run,..a zone of maximum .conversion and maximumftemperaturewhich proceeds from. the point adjacent the entrance of the reactor to apoint adjacent the exit thereof. "Such concentrations of the'heatgenerated by the exothermic reaction are deleterious since they promoteproduction of tarry material, degradation of the catalyst granules andthe setting of the consolidated mass into a rigid structure. ,Theinclusion of thegranularnon-catalytic material in the catalyst mass inaccordance with this invention minimizes the maximum temperature reachedin the reaction mass by enlarging the zone in which reaction occursprincipally and by providing heat adsorptive material at the zone ofmaximum temperature which adsorbs heat and assists in 'its'transferfrom-the zone of maximum temperature. In this manneroverheating of thecatalyst is minimized andthe useful life of the catalyst is lengthened.

As mentioned above carbonaceous materials are preferredasthenon-catalytic granular material since they may be obtained in thedesired granular'form without the necessity of pelleting or extrusion..While coke from the .carbonization of coal or petroleum may be employedit is less desirable.thancharcoal since the coke may contain substantialquantities of sulphur which may contaminate the hydrocarbon product.Coke producedfby the carbonizationof coal may have the furtherdisadvantage that it containsresidual or ash-like materials whichareireactive with the pyrophosphate and its reduction products inthemanner. described above. Granular charcoal is, therefore, preferredalthough :the use 'of "other suitable "granular or "pelletedcarbonaceous materials isnot'excluded.

The granular spacer materialshould be suffi- Iciently'coarsertogpreservein the catalyst mass the desired" permeability, but the use of granularsizes larger than necessary is undesirable since the advantages of theinclusion of this material in the catalyst mass are realizedto thefullest degree when the spacer is distributed most uniformly throughoutthe catalyst mass. Conviently the spacer material may be ofapproximately the granular size of the catalyst granules or pelletsalthough this is not essential.

The reaction conditions employed when using a catalyst mass containingsubstantially noncatalytic spacer "material in accordance with thisinvention are substantially like the reaction conditions which areemployed when using a similar catalytic material without the inclusionof the non-catalytic granular material in the catalyst mass. However,certain adjustments in the temperature and space velocity may berequired to compensate for the difference between the volume of thecatalyst mass and the space actually occupied by the catalytic material.In the polymerization of olefin hydrocarbons any suitable pressure maybe used but it is preferred to employ relatively high pressure, forexample in excess of 150 pounds per square inch, although atmosphericpressure or lower pressures may be employed. The reaction temperaturedepends somewhat upon the nature of the material under treatment of theproduct desired. In the conversion of gaseous olefins, such as butylenesand propylene, temperatures of 300 to 500 F. may be employed. In theconversion of hydrocarbon gases the hydrocarbon should be passed overthe contact material at a rate of 2 to 50 cu. ft. (measured as gas atstandard conditions of temperature and pressure) per pound of catalyticmaterial per hour. Otherwise expressed the hydrocarbon reactants shouldbe passed through the reactor at a rate of 50 to 6000 volumes per hourper volume of the catalyst mass. However, the space velocity is governedalso by the degree of conversion desired. In a treatment of gaseousmixture containing iso-butylene it may be desirable to operate at arelatively high space velocity to limit the extent of conversion to theco-polymerization of iso-butylene or the inter-polymerization ofiso-butylene and normal butylenes.

The activation of olefinic hydrocarbons in other condensation reactionsis carried out suitably at somewhat the same conditions as are employedin the polymerization reaction. In the propylation of aromatichydrocarbons the above ranges of conditions of temperature, pressure andspace velocity are satisfactory. For example in the propylation ofbenzene the mixture of benzene, propylene and accompanying inerthydrocarbons may be passed over the catalyst mass under a pressure of900 pounds per square inch at a temperature of 400 to 450 F. and at arate of 11 cu. ft. per hour per pound of catalytic material (exclusiveof spacer). In alkylation treatments it is desirable also that thehydrocarbon to be alkylated by the olefin be present in the reactionzone in substantial excess in order to minimize copolymerization of theolefin reactants. In the alkylation of aromatic hydrocarbons by means ofolefin hydrocarbons the mol ratio of aromatic to olefin hydrocarbonsshould be in excess of 1:1 and preferably should be 5:1 or higher.

The granular spacer material and granular catalyst may be mixedsufficiently by charging them to the reaction zone simultaneously orthese materials may be mixed outside the reactor before charging thereactor. Alternatively the spacer and catalyst granules may be arrangedin the reactor as alternate relatively thin layers extendingtransversely to the path of flow of the reactants. This arrangement canbe secured by charging alternate quantities of spacers and catalyst tothe reactor. With any of the above operations it may be desirable toprovide larger bodies of the granular spacer material at one or moreplaces in the reactor. For example, a substantial layer of granularspacer material may be placed at the bottom of the reaction zone or inthe bottoms of a plurality of elongated tubular reaction zones.

This application is a division of my co-pending application Serial No.470,687, filed December 30, 1942, now Patent 2,414,206.

I claim:

1. The method of polymerizing olefin hydrocarbons which comprisespassing said olefin hydrocarbons at elevated temperature through aconsolidated granular mass essentially consisting of an intimate mixtureof catalyst granules and spacer granules, said spacer granules being inphysical non-adhering contact with said catalyst granules, said catalystgranules comprising an intimate mixture of phosphoric acid and finelydivided supporting material therefor, and said spacer granules beingcomposed of charcoal and sufficiently coarse to preserve in the catalystmass the desired permeability.

2. The method for alkylating aromatic hydrocarbons which comprisespassing said aromatic hydrocarbons and olefin hydrocarbons at elevatedtemperature through a consolidated granular mass essentially consistingof an intimate mixture of catalyst granules and spacer granules, saidspacer granules being in physical non-adhering contact with saidcatalyst granules. said catalyst granules comprising an intimate mixtureof phosphoric acid and finely divided supporting material therefor, andsaid spacer granules being composed of charcoal and sufficiently coarseto preserve in the catalyst mass the desired permeability.

3. The method for alkylating benzene with propylene which comprisespassing benzene and propylene at elevated temperature through aconsolidated granular mass essentially consisting of an intimate mixtureof catalyst granules and spacer granules, said spacer granules being inphysical non-adhering contact with said catalyst granules, said catalystgranules comprising an intimate mixture of phosphoric acid and a finelydivided supporting material therefor, and said spacer granules beingcomposed of charcoal and sufficiently coarse to preserve in the catalystmass the desired permeability.

4. The method of activating olefin hydrocarbons in condensationreactions which comprises passing the hydrocarbons which enter into thecondensation reactions, under suitable reaction conditions oftemperature, pressure and space velocity, through a consolidatedgranular mass essentially consisting of an intimate mixture of catalystgranules and spacer granules, said spacer granules being in physicalnon-adhering contact with said catalyst granules, each of said catalystgranules comprising an intimate mixture of phosphoric acid and finelydividedsupporting material therefor, and each of said spacer granulescondensation reactions. under suitable reaction conditions" oftemperature, "pressure "and space velocity, through a consolidatedgranular mass essentially consisting of an intimatemixture' of catalyst,granules and spacer: granules, said spacer granules-being in physicalnon-adheringcontact with said catalyst granules, said catalyst granulescomprising an intimate mixture of phosphoric acid-and finely dividedcharcoal, and each of saidspacer; granules being composed of charcoal rand sufficientlyooarse to preservein the catalyst mass the desiredpermeability.

'6; The method for 1 activating olefin hydrocarbons in a condensationreaction which comprises passing the hydrocarbons'rwhichenter into thecondensation reaction, under suitable reaction conditions oftemperature, pressure and space velocity, through a consolidatedgranular mass essentially consistin of anintimate mixture of catalystgranules and spacer granules, said spacer granules being in physicalnon-adhering contact with said catalyst granules, said catalyst granulescomprising an intimate mixture of phosphoric acid with kieselguhr assupportin material therefor, and said spacer granules being composed ofcharcoal and sufficiently coarse to preserve in the catalyst mass thedesired permeability.

7. The method for activating olefin hydrocarbons in a condensationreaction which'comprises passing the hydrocarbons "which enter into thecondensation reaction, under suitable reaction conditions :oftemperature, pressure and space velocity, through a consolidatedgranular mass essentially consisting of an intimate'mechanical mixtureof separate catalyst granules and spacer granules, said spacer granulesbeing in' physical substantially non-adhering contact with said catalystgranules, saidcatalyst granules comprising. an vintimatezmixtureofphosphoric acid and finely divided supporting material therefor,vandsaid spacer granules i being "composed of charcoal and sufiicientlycoarse to preserve in the catalyst mass thedesired permeability, thevolumetric ratio 'of said catalyst granules to said spacer granulesbeing between about 1:1 and about 5-: 1.

-EDWIN T. vLAYNGr.

REFERENCES, CITED The following references are of record in the file ofthis patent:

- UNITED :STATES. PATENTS Number Name Date 2,116,151 'I'patie'fi'et a1May 3, 1938 2,287,931 Corson et al June30, 1942 FOREIGN. PATENTS NumberCountry Date :1'71768 Australia May 29, '1935

4. THE METHOD OF ACTIVATING OLEFIN HYDROCARBONS IN CONDESATION REACTIONSWHICH COMPRISES PASSING THE HYDROCARBONS WHICH ENTER INTO THECONDENSATION REACTIONS, UNDER SUITABLE REACTION CONDITIONS OFTEMPERATURE, PRESSURE AND SPACE VELOCITY, THROUGH A CONSOLIDATEDGRANULAR MASS ESSENTIALLY CONSISTING OF AN INTIMATE MIXTURE OF CATALYSTGRANULES AND SPACER GRANULES, SAID SPACER GRANULES BEING IN PHYSICALNON-ADHERING CONTACT WITH SAID CATALYST GRANULES, EACH OF SAID CATALYSTGRANULES COMPRISING AN INTIMATE MIXTURE OF PHOSPHORIC ACID AND FINELYDIVIDED SUPPORTING MATERIAL THEREFOR, AND EACH OF SAID SPACER GRANULESBEING COMPOSED OF CHARCOAL AND SUFFICIENTLY COARSE TO PRESERVE IN THECATALYST MASS THE DESIRED PERMEABILITY.